In general, a heat exchanger is an apparatus for moving heat between two fluids and is widely used for cooling, heating, and hot water.
The heat exchanger may function as a waste heat recovery heat exchanger for recovering waste heat, may function as a cooler for cooling a high temperature-side fluid, may function as a heater for heating a low temperature-side fluid, may function as a condenser for condensing a refrigerant or may function as an evaporator for evaporating a refrigerant.
The heat exchanger may be used in a heat pump, that is, a cooling and heating apparatus for transferring a heat source of a low temperature at a high temperature using the generation of heat or condensation heat of a refrigerant or transferring a heat source of a high temperature at a low temperature.
The heat pump may include a compressor, a heating and cooling switchover valve, an outdoor heat exchanger, an expansion device, and an indoor heat exchanger. In the heat pump, upon cooling operation, a refrigerant may flow in order of the compressor, the heating and cooling switchover valve, the outdoor heat exchanger, the expansion device, the indoor heat exchanger, the heating and cooling switchover valve, and the compressor. In the heat pump, upon heating operation, a refrigerant may flow in order of the compressor, the heating and cooling switchover valve, the indoor heat exchanger, the expansion device, the outdoor heat exchanger, the heating and cooling switchover valve, and the compressor.
In the heat pump, in a heating operation of a low temperature in which an outside temperature is low, frost can be easily attached to the outdoor heat exchanger due to outdoor air of a low temperature. The heat pump may include a separate defrosting heater for heating the outdoor heat exchanger. Accordingly, in a condition in which excessive frost is attached to the outdoor heat exchanger, the heat pump can remove frost attached to the outdoor heat exchanger by heating the outdoor heat exchanger using the defrosting heater. Meanwhile, upon heating operation, in a condition in which excessive frost is attached to the outdoor heat exchanger, the heat pump can remove the frost of the outdoor heat exchanger by performing a defrosting operation for changing the direction in which a refrigerant flows as in a cooling operation.